1. Field of the Invention
This invention relates to a device for detecting clogging of a pipe through which fluid flows, especially pulverized objects, slurry, and similar fluids.
2. Related Background Art
In a polyolefin production plant, for example, polyolefin produced in a fluidized bed olefin polymerization reactor is transported to a reactor of a next process, or a reservoir through a transportation pipe.
Temperature at the exit of the fluidized olefin polymerization reactor and in a pipe for the transportation is 60.degree.-100.degree. C. At this temperature range polyolefin has such high viscosity and solidification that there is a risk that it may clog the transportation pipe.
To avoid such risk in transporting polyolefin from the fluidized bed polyolefin polymerization reactor to a next process, generally a pressure difference of 3-25 kg/cm.sup.2 is generated between the polymerization reactor and the next process to transport the polyolefin at high speed by the pressure difference.
Conventionally, the clogging of the transportation pipe is prevented by transporting polyolefin at high speed, but still the transportation pipe tends to clog. In the fluidized bed olefin polymerization reactor, for example, sometimes lumps are formed in the reaction process, and the lumps stick to valves of the transportation pipe and clog the pipe.
To detect clogging of the transportation pipe, conventionally operators on patrol press a sound scope stick against the transportation pipe and directly listen to vibratory sounds of the transportation pipe caused by the flow of polyolefin to detect the occurrence of clogging.
Thus, the detection of clogging of the transportation pipe of the polyolefin depends on human audition. Such detection results sometimes contain personal differences, and there is a risk that clogging may be overlooked.
Since the patrol is periodic, if the transportation pipe are clogged immediately after a patrol, the operation is continued with the clogging unremoved, and a clogging state is worsened. When the operation is continued with the clogging state unremoved, the clogging material is solidified, and the transportation pipe sometimes has to be removed and changed.
But, since the polyolefin is transported through the transportation pipe at a flow rate as high as 10-300 m/s, it is very difficult to utilize flow meters and electrodes. The presence of projections, such as flow meters, electrodes, etc., in the transportation pipe can be sources of the clogging and adversely enhance the clogging.
The above-described problem is not limited to the transportation pipe for polyolefin and arises in transportation pipes for other pulverized materials, slurry, etc.